Dust door arrangement for video cassettes

ABSTRACT

A dust door arrangement which avoids spring clip malfunction and enhances video cassette longevity. Reduced width of cavities containing first and second side hinges between the dust door and the video cassette cover improve hinge flexibility and operation and eliminate hold down spring clips catching when the video cassette is being withdrawn from a VCR. The dust door, hinge and cover are integrally molded, with the hinge lying below the surface of the cover of the video cassette and providing an axis of rotation for the door with respect to the cover. The hinge and cavity are approximately of the same width and are about two to four times as wide as the thickness of the dust door side walls. A supplemental spring is preferably provided to bias the dust door downward. The dust door first and second thin side walls have bevelled tops with extended steps which form first and second hinges. Flat tops of the hinges oppositely mate with first and second extensions extending down from the cover. The bevelled tops have angles of less than 30% to reduce angle of incidence. The width of the hinge is greater than the width of the thin side walls, but no greater than four times the width of the side walls. The width of the downward extensions approximate the width of the hinges. At least one of the side walls of the dust door has a tape leader viewing access for providing visual access to the tape leader without raising the dust door.

This application is a division of application Ser. No. 07/886,152, filedMay 21, 1992, now U.S. Pat. No. 5,308,015.

BACKGROUND OF THE INVENTION

The present invention relates to integrally molded video cassettes.Specifically, the present invention addresses dust doors integrallyhinged to video cassette covers.

The molding of dust doors on video cassettes with living hinges is arecent advent in the art of video cassette manufacture. The impetusbehind providing a dust door in integral relation with a video cassetteis primarily reduction of labor, reduction of parts, accuracy andsimplicity of manufacture associated therewith, recyclability of thesubstantially uniform cassettes, and further improvements in the art ofmolding. Through continued testing of this technology, it has been shownthat further improvements in conjunction with the hinges improveperformance of the video cassettes and the dust doors when moving intoopened position in a player and into closed position when removed from avideo cassette recorder.

Several important goals exist as with previous devices. One relates tothe ability of an integrally molded hinge to maintain strength wellbeyond the life of the video cassette. Previous hinges were relativelywide to maintain elasticity and resist breakage. However, it has beenfound that the width previously thought necessary to maintain hingestrength may cause jamming of the cassette within a small number ofmachines because of a hold down spring clip, platen or roller movinginto depressions by the hinges. When the cassettes are inserted intovideo cassette recorders, tops of cassettes are held downward while thedust doors are moved upward to expose the video tape. Upon removal ofthe cassettes, spring clips or rollers in the machines slide across thetop surfaces of the covers of the cassettes and over the dust doors. Itis typical for dust covers to have short side portions which are hingedto the cassette side walls in indentations or cavities along the sidesof the cassette. The indentations approximate the thickness of the doorside portions. If those indentations are made too wide, as waspreviously thought necessary to accommodate wide hinges, the hold downspring clips can slip into the wide recesses and can jam a cassette ormachine or prevent raising of the doors.

The hinges are attached to sides of the dust doors. The angles of thehinged extensions are important for proper functioning of the springclip. A severe angle can cause jamming. The present invention addressesthe potential problems of jamming due to wide hinges and severe anglesin dust door hinge arrangements.

Another problem solved by the invention relates to the detection oftapes which have not been rewound. With prior cassettes, the user orrental employee had to lift the dust door to see if the clear leader waspresent, thus indicating a fully wound tape, or otherwise look through aclear window inserted in the cassette's cover.

The present invention also provides solutions to previous problemsrelated to supplemental spring arrangements for dust door biasing.

SUMMARY OF THE INVENTION

The present invention is a dust door arrangement for video cassettes.The dust door and video cassette cover are preferably integrally moldedand joined by plural living hinges. At least one of the hingespreferably cooperates with a supplemental spring attached to thecassette and to the door proximally to the hinge to bias the door closedwith respect to the cassette.

The spring incorporates a door attachment end and a cassette attachmentend for fitting within door and cassette spring receptors respectively.The spring moves longitudinally in guides as it torques and restoreswhile the dust door is opened and closed.

A dust door side wall notch or window or a transparent door sideprovides access for clear leader viewing or light sensing withoutopening the door. Sides of the dust doors are relieved, notched orbevelled so that clear tape leader signalling lights may be viewedthrough openings in the indented portions of the cassette sides whilethe dust door is closed.

The dust door has a front face for covering exposed video tapes when inthe closed position, and first and second opposite side walls extendingperpendicularly from the front face toward first and second side hinges.The side walls have rear edges. The hinges are molded to the rear edgesand oppositely to first and second downward extensions of the cover. Therear edges of the dust door preferably have bevelled tops. The hingesare molded oppositely to downward edges of the downward extensions andthe bevelled rear edges. That positions the hinges below a plane asprovided by a top surface of the cover and the top of the dust door,forming an axis of rotation of the dust door with respect to the coverbelow that plane.

Preferably the indentations of the cassette side walls for receiving thehinge are less than or equal to four times the thickness of the sidewalls. That permits hinge widths of about two to four times the wallthickness, which has been found to provide substantial hinge life andstrength.

The hinges preferably have flattened extended upper surfaces and notchedlower surfaces, with the axes of rotation at the notches. The extendedflat upper surfaces improve hinge operations. A coil of the supplementalspring is provided adjacent the lower surface of the notch. A first legis attached to the dust door and a second leg slides in and out of thecassette. A preferred spring is a spring having a central coil andoffset opposite dust door attachment and cassette attachment ends. Thecoil is positioned below or adjacent the notched lower surface of thehinge. That biases the dust door at its axis of rotation.

A coil retaining means is preferably provided adjacent the coil forholding the coil in close relation to the notched lower hinge surface.

The retaining means may be an abutment molded perpendicularly downwardfrom the cover. The coil is positioned between an exterior face of thedownward abutment and an interior face of the door side wall with awidth of the coil approximating a width between the interior face of theside wall and the exterior face of the abutment. That restricts lateralmovement of the spring.

The dust door spring end attachment means is generally near the top ofthe interior face of the side wall, substantially above the placement ofthe coil with the coil tensed near the axis for biasing the dust doordownward in the closed position.

Since the spring coil is positioned beneath the notch, the coil moves asthe dust door is raised and lowered. The outer end of the spring isfixed in the dust door. The inner leg of the spring moves in and outthrough an opening in a front facing portion of the side wall at theedge of an indentation in the side wall.

The integrally molded cassette and door are preferably made of apolypropylene material.

In an alternate preferred embodiment, the dust door side wallincorporates a clear leader viewing means. Some cassettes incorporatewindows on the side of the shell through which the tape can be seen. Inothers, the tape is exposed across the front and partially along theside walls. The present side walls of the dust door incorporate windowor leader access means to view the tape without raising the dust door. Anotched rear edge, an aperture, or an opaque or clear side wall arepreferred access means. Those can be provided on integrally molded videocassettes, or on traditional cassettes with doors molded separately andattached during cassette assembly. The access means is a new embodiment,and an improvement over the prior art.

A preferred dust door arrangement for video cassettes has a dust doorintegrally molded to a video cassette cover for rotation on the cover atfirst and second side hinges. The dust door has a front, a top and firstand second opposite side walls. The dust door is made of uniformthickness. The side walls substantially overlap first and second sidesof the video cassette with the dust door front covering a front face ofthe video cassette when the dust door is in a closed position. At leastone of the rear edges of the side walls has a bevelled top portionangling from the top of the dust door downward toward a moldedattachment inward extension which also extends rearward, with a flatupper surface and a lower notch forming a hinge therebetween. The hingeis less than or equal to four times the width of the thin side wall formaximizing strength and prolonging use while providing a smooth hinge,and is oppositely molded to a downward extension extending downward froma side edge portion of the cover. The sloped downward extension can havea width ranging from the same width as the side wall to four times thewidth of the side wall. The width of the downward extension canapproximate the width of the hinge, yet is minimized for prevention ofspring clip jamming. The sloped extension ends in the flat forwardextension with the notch below a flat upper surface which forms thehinge. A supplemental spring may be provided proximal the hinge forbiasing the dust door to the closed position. The spring has a dust doorattachment end and a cassette attachment.

The spring is preferably a coil spring having a central coil positionedproximal the hinge. The spring has a dust door attachment end fixedlyattached to the dust door and a cassette attachment end slidablyattached to the video cassette.

In a preferred embodiment, the width of the downward extension and hingeare approximately the same, and the width of the thin side wall isapproximately one half of the width of the hinge.

A molded connection between the thin side wall and wider hinge describesa step a given distance from an axis of rotation for the hinge. Thedownward extension and bevelled edge mate at the hinge, providing theaxis of rotation a given distance on the side wall from the side edge ofthe cover. The distance between the axis of rotation and the side edgeof the cover is preferably greater than the distance between the axis ofrotation and the step so that the step does not protrude above the coverupon rotation of the dust door. That minimizes incidence of spring clipcatch.

In one embodiment, the thin side wall is approximately 1 mm thick andthe hinge is about 3 mm wide. The notch or indentation in the side wallis about 3.5 mm, leaving a 0.5 mm clearance.

The angle of the bevelled edge with respect to the top of the door ispreferably less than or equal to 30%, reducing spring clip incidentangle to prevent spring clip catching in the dust door side notch.

The present video cassette is produced at a substantial savings inmaterials and elements, number of parts and labor, with improvedquality. The cassette is totally unique.

The preferred cassette weighs 1.5 oz to 1.8 oz less than a standardcassette, resulting in postage savings for direct mail applications.

In a preferred embodiment, the cassette eliminates windows to allow fora full wrap around face and spine label. That innovative look mayeliminate the need for the box board sleeve in several applications.

Preferably the cassette is available in a range of colors, and the useof polypropylene versus the standard polystyrene gives the cassette aunique feel and lubricity, reducing dropouts and improving the product.

A preferred video cassette has a reel flange positive engagement brakingsystem, an integral pressure flap, dust door and tape guides. Thecassette is totally recyclable. The present cassette easily surpasses100 and more plays with no increase in dropouts. Independent testing hasshown the cassette to perform on par with the dropout performance of apremium A shell and to have far fewer dropouts than a standard B shell.

Testing on the present dust door has shown it to be capable of cyclingmore than 10,000 times. The engineering of the cassette has resulted inthe elimination of more than 25 parts, the consequence of which isproduct consistency and reliability. The fully automated manufacturingdemonstrates superior consistency versus a standard cassette, which has30 hand assembled parts.

Preferably the cassette is source reduced and manufactured fromcompatible plastic materials. The cassette can be completely recycled,tape and label included, with minimal disassembly of the product. Theproducer of the cassette, is establishing a recycling operation toconvert the material into next generation products. The present cassettecan be produced of recycled material with no sacrifice in productquality. It is the only video cassette in the world which hasresponsibly addressed the environmental issue in a proactive fashion.

In a preferred embodiment, the cassette holds 65 minutes of tape (SP)and 195 minutes (EP) and performs excellently with all grades of topcoated tape. Back coated tape is not recommended since it tends to dragin fast forward and rewind.

These and further and other objects and features of the invention areapparent in the disclosure, which includes the above and ongoing writtenspecification, with the claims and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a preferred video cassette with the preferred narrow livinghinges and supplementary spring.

FIG. 2 is a side view of a preferred hinge and door arrangement with thedoor in the closed position.

FIG. 3 is a side view showing the door raised.

FIG. 4 is a cutaway side view showing the hinge, door and supplementaryspring.

FIG. 5 is a front view of the open door and spring.

FIG. 6 is a top view of the cover, hinge, door and spring arrangement.

FIG. 7 is a perspective of a first side hinge.

FIG. 8 is a perspective of the opposite side hinge.

FIGS. 9 and 10 are perspective views showing alternative window accessmeans, apertures in the dust door side wall and opaque or clear sidewall respectively.

FIGS. 11-14 show window or leader access means provided on a dust doorside wall.

DETAILED DESCRIPTION OF THE DRAWINGS

As shown in FIGS. 1, 2 and 3, a video cassette, generally indicated bythe numeral 1, incorporates a base, a rear wall 2, a cover 3 and a dustdoor generally indicated by the numeral 5. The dust door 5 is integrallymolded with the cover 3 on first and second hinges 7 and 8. The hingesand adjoining structures are located in cavities 45 and 46 at the sidesof the cover near a front 16 of the cassette. The dust door 5 moves asper arrow 12 in FIG. 3 on an axis of rotation 10 provided by the firstand second hinges 7 and 8.

In the preferred video cassette as shown in FIG. 1, reel springs 16 aremolded within the cover to press the reels downward. No windows areprovided to view tape position. A label lies flat on the cover. Thelabel may have a tear-off portion that surrounds the front, back andbottom of the cassette, eliminating a need for a shipping sleeve.

The hinges 7 and 8 are provided between the cover 3 and door 5 on firstand second sides 20 and 19 near the front 16 of the video cassette 1.

The dust door 5 incorporates a front face 17, a top 15, approximately inthe same plane as the top of the cover 3, and first and second sides 35and 37 which may be approximately identical. The sides have rear edges31, bevelled top edges 13 and bottom edges 33.

As shown in FIGS. 2 and 3, the sloped edge 13 angles downward from thetop 15 of the dust door to a flat surface 14 which extends rearwardtoward the rear edge of the side wall recess to sloping surface 11. Theflat portion 14 and the notched surface 28 form the hinge 8.

The hinge 8 incorporates a flat upper extension surface 14 and a lowersurface 28. The hinge 8 oppositely attaches to a downward extension 11extending from the cover 3 downward along the side 19 of the cassettetoward the front face 12. The lower surface 28 of the hinge 8 canpreferably have a notch 29 or groove, as shown in FIG. 2. That grooveestablishes the axis of rotation 10 and further assists in nesting andfulcruming a supplemental spring 9 positioned adjacent or under thehinge.

The supplemental spring 9 assists the hinge in biasing the dust doordownward, and generally prolongs the life and improves the operation ofthe video cassette. A preferred spring 9 is a coil spring having acentral coil 27, a dust door attachment end 23, and an opposite cassetteattachment end 25. The opposite ends are laterally offset as is typicalfor coil springs. The coil 27 is a cylindrical structure which ispreferably mounted either coaxially with the axis of rotation, or withits outer circumference abutting part of the notch which forms the axisof rotation.

In a preferred embodiment, the door attachment end 23 of spring 9 isfixedly attached to the door by a dust door end receptor 21 provided onthe door 5. The receptor 21 can be sited on the dust door interior nearthe top 15, creating torsion on the central coil 27 which is positionednear the axis of rotation 10 and biasing the dust door downward in theclosed position. The cassette attachment end 25 of spring 9 ispreferably mounted within a cassette attachment end receptor 41, shownby the dashed line in FIG. 2. The receptor can be an aperture providedin the shell of the cassette into which the end 25 is inserted and isfree to slide along its length. That sliding motion as shown in FIG. 3is imparted by raising the dust door, as shown by arrow 12.

As the cassette is inserted into a video cassette recorder, the dustdoor is raised by a mechanism to expose a tape 43 running across theface of a video cassette. The fixed attachment between the receptor 21and the door end 23 pulls the central coil 27 forward and around theaxis of rotation 10. Sliding the coil along wall 28 which is extendeddownward from the cover. The sliding attachment between the cassettespring end receptor 41 and the cassette attachment spring end 25 allowsthat movement, thereby maintaining approximately even torsion of thespring on the door as the door travels from closed to open positions andvice versa. Maintaining a relatively constant spring pressure on thedust door regardless of its position is important to the presentinvention, it permits smooth operation of the door. Variable tensionmight lead to damage of the cassette and VCR, and might further promotejamming.

The flat upper surface 14 extends the axis of rotation 10 forward on thevideo cassette. It has been found that forward placement greatly reducespotential spring clip catching incidence. Further, the surface 14provides a larger hinge area, which increases wear life of the hinge.

FIG. 4 shows an interior view of the hinge 7, having a flat uppersurface 14, a notched lower surface 29 prescribing the axis of rotation10. A supplemental spring 9 is shown by hinge 7, although it isdesirable to use only one spring by one hinge. The coil 27 of the spring9 abuts the forward portion of the notch near the axis of rotation 10for revolving thereabout as indicated by arrow 45 when the dust door 5is lifted. The fixed attachment between the receptor 21 and the dustdoor spring end 23 pulls the coil 27 around the axis 10 when the dustdoor is lifted, and maintains approximately constant downward pressureon the door due to the changing of the position of the coil around theaxis 10.

FIG. 5 is a frontal view of the video cassette showing the door 5 in theopen position. The door 5 preferably provides some clearance 51 whenlifted to expose the front 16. The cover 3 preferably has a downwardlyextending abutment wall 28 adjacent the coil 27 to hold the coil inalignment when the spring slides during door operation. The cassette mayalso incorporate a cassette spring end track or abutment for aligningand holding the cassette spring end during sliding. Opposite theabutment 28, the spring dust door side 35 has an interior wall 49 whichabuts the opposite side of the cylindrical coil 27, maintainingalignment of the coil around the axis of rotation during operation ofthe door.

FIG. 6 shows the hinge 7 and spring 9 from a top view. The coil isplaced between the abutment 28 and the wall 49. The cassette endreceptor 41 is shown as an aperture in the cassette shell or housing,and can be supplemented or replaced with a track or cassette end guide.

FIGS. 6, 7 and 8 show the dimensions of the dust door side wall 15, thedownward extension 11, the bevelled rear edge 13, a step 47 formed onthe bevelled edge 13 of the door side wall for widening the hinge 8 tobetween two and three times the wall thickness. A cavity 48 is formedabove the hinge, downward extension and bevelled edge 13 near theforward extension 50 of the cover. Also shown in FIGS. 7 and 8 is anaccess notch 49 provided in the dust door side 15 for allowing access toview a clear leader when the dust door is in the closed position. Thenotch in the dust door side wall is provided for optical accessdetection of a clear leader on a reel tape end by eye or light when thedoor is closed.

In FIG. 8, cavity width C is shown to approximate the width of the hinge7. The hinge width is shown to be approximately twice the width of theside wall 15. FIGS. 7 and 8 show hinge structures for opposite hinges 7and 8. The structure of each is preferably approximately the same,although supplemental springs can be provided under one or both hinges.The narrowed width C of the cavity 48 is important. Previous inventionshad widths of 0.250 inches or greater. It has been found that at thosewidths, certain types of cassette hold down devices in a small number ofvideo cassette recorders are prone to catching. An object of the presentinvention is to have a cavity width of less than 0.250 inches. Apreferred cavity width C is 0.140 inches, approximately twice the widthD of the bevelled edge 13 and side wall 15 of 0.070 inches. The strengthand longevity of the hinges are adequate after narrowing. Smoothness ofoperation and accommodation of slight hinges axis misalignments, if any,may be improved by narrowing the hinges.

It is not necessary for the cavity width C to be the same as the hingewidth. However, it is preferable that the hinge width be no greater thanfour times the thickness D of the door side wall.

The differing widths between the hinge and the bevelled edge of the sidewall are accommodated by a step 47, a given distance B from the flatsurface of the hinge, which is near the axis of rotation of the dustdoor. It is preferable for that step distance B to be less than adistance A defined between the top of the flat surface, or the axis ofrotation, and the top of the cover. Because B is less than A, revolutionof the step 47 upwards due to rotation of the dust door does not causethe step to protrude above the top surface of the cover. That step isfunctional in avoiding any hold-down interference during cover lifting.

Through repeated testing of prior art, it has been found that the angleof the bevelled edge 13 is also important to eliminate hold-down orspring clip catching. It has been found that angles above 30° result ina greater than normal incidence. The present invention provides an angleα of less than or equal to 30°, thus eliminating that problem.

One object of the present invention is to provide a maximum width Eacross the front top surface of the cover proximal the front 16, therebyreducing incidence of spring clip catching.

Because of the large numbers and variation of video cassette recorders,including the variety of placement of spring clips, a primary object ofthe present invention is to reduce the profile of the hinges needed forfunction of the dust door.

The present preferred hinges have widths of two times, three times orfour times the thickness of the sides of the dust door. Width C of thecavity is reduced from the applicant's prior devices; the angle ofincidence between the spring clip and the dust door, which is the angleprovided by the bevelled edge, is reduced; and portions of the door andhinge protruding above the top surface of the cover due to rotation ofthe door are eliminated.

In most VCRs, spring clips or rollers typically are provided to pressdown on the cover of the cassette to bias the cassette downward, toprovide flexible top guidance, and to assist in reclosing the dust doorupon removal from the machine. It is a principal object of the inventionto provide low profile narrow hinges that will not interfere with theaction of the hold down spring clips.

As shown in FIG. 7, a tape leader window access 49 can be a notch in thelower back edge of the side of the dust door. Alternatively, as shown inFIG. 9, the window access means can be an aperture 51, or in FIG. 10 thedust door side can be an opaque or clear wall 53. The window accessmeans 49 provides a more versatile video cassette. The end of a tape ina cassette is typically clear; therefore, a user or video rental storeemployee can readily look through the window access means and seewhether a tape has been rewound without raising the dust door.

FIGS. 11-14 show an alternative form of a dust door 55 molded with theshell 56. The doors have window access means. In FIGS. 11 and 12 showingthe door in the closed and opened positions, the door 55 has a solidside wall with an aperture 51 for access to the window 52 for viewingthe tape without raising the lid. The aperture is aligned with thewindow in the closed position. FIGS. 13 and 14 show the window accessmeans as a notch 49 for accessing the window 52 to view a clear leaderof a tape. The advantages of tape leader optical access through a closeddoor are obtained by this invention, whether or not the dust door isintegrally hinges to the cassette. The improvements have enhancedadvantages in the integral hinge cassettes since tape reel viewingwindows are avoided.

While the invention has been described with reference to specificembodiments, modifications and variations of the invention may beconstructed without departing from the scope of the invention, which isdefined in the following claims.

We claim:
 1. Video cassette apparatus comprising a dust door integrally molded to a video cassette cover for rotation on the cover at first and second side hinges, the dust door having a front, a top and first and second opposite side walls, the side walls overlapping first and second sides of the video cassette with the dust door front covering a front face of the video cassette when the dust door is in a closed position, at least one rear edge of the side walls having a bevelled top portion angling from the top of the dust door downward toward a molded attachment with the hinge, the hinge being less than four times wider than a thickness of the side wall for maximizing strength and prolonging use, and the hinge oppositely molded to a downward extension extending downward from a side edge of the cover.
 2. The apparatus of claim 1, further comprising a supplemental spring provided proximal the hinge for biasing the dust door in the closed position, the spring having a dust door attachment end and a cassette attachment end.
 3. The apparatus of claim 2, further comprising the spring being a trap spring having a central coil positioned proximal the hinge, a dust door attachment end fixedly attached to the dust door and a cassette attachment end slidably attached to the video cassette.
 4. The apparatus of claim 1, further comprising the width of the downward extension and hinge being approximately equal, and the width of the thin side wall being approximately one half of the width of the hinge.
 5. The apparatus of claim 1, further comprising the width of the side wall being approximately 0.07 inches wide.
 6. The apparatus of claim 1, further comprising the angle of the bevelled edge with respect to the top of the door being less than or equal to 30° to reduce spring clip incident angle to prevent spring clip catching on the dust door side.
 7. The apparatus of claim 1, further comprising a first and second cavity provided in the cover of the video cassette for first and second side hinges respectively, the downward extensions extending downward from a side edge of the cover within the cavities, the width of the cavities being less than four times the widths of the sides of the door.
 8. The apparatus of claim 7, further comprising the width of the cavity being less than 0.250 inches.
 9. The apparatus of claim 7, further comprising the width of the cavity being approximately two times the width of the thin side wall.
 10. The apparatus of claim 7, further comprising the cavity having a width of approximately three times the width of the thin side wall.
 11. The apparatus of claim 7, further comprising the downward extension and hinge having approximately the same width.
 12. The apparatus of claim 7, further comprising the downward extension having approximately the same width as the cavity. 